Sensitivities of rainfed maize production to root zone soil water, air temperature and shortwave radiation in the Sanjiang Plain under sub-humid cool-temperate climates

Development of rainfed maize (Zea mays L.) is sensitive to fluctuations of environmental conditions, while whether the sensitivity varies across the growth stages is still unclear. Based on a 5-year dataset collected from consecutive observations, this study examined the sensitivities of biomass and yield production of rainfed maize to root zone soil water, air temperature and shortwave radiation at four growth stages in the Sanjiang Plain of Northeastern China under sub-humid cool-temperate climates. The multiple linear regression model was employed to establish functional relations between biomass and yield production and significant explanatory variables. A Monte-Carlo simulation was used to test sensitivities of biomass and yield production to perturbation of a single significant explanatory variable or co-perturbation of multiple significant explanatory variables. Results showed that root zone soil water prevailed over air temperature and shortwave radiation in affecting rainfed maize development for the most time of the growing period. Biomass production was most sensitive to root zone soil water which had positive variance contributions of 70 – 100% at the early and late vegetative stages and a negative variance contribution of −99.4% at the early reproductive stage. Yield production was also sensitive to root zone soil water at the early reproductive stage with a 100% positive variance contribution. Biomass and yield production were most sensitive to air temperature at the late reproductive stage and the positive variance contributions of air temperature were 97.7 – 100%. Shortwave radiation negatively contributed to biomass production by −28.6% at the late vegetative stage. The findings of this study suggest that more attention could be paid to the most sensitive factor at different growth stages of rainfed maize for great biomass accumulation and high grain yield.